Location：1、 Casting
Casting is the process of melting metal into a liquid that meets certain requirements and pouring it into a mold. After cooling, solidification, and cleaning treatment, a casting (part or blank) with predetermined shape, size, and performance is obtained. It is the basic process of modern mechanical manufacturing industry
The cost of casting produced blanks is low, and for parts with complex shapes, especially those with complex inner cavities, it can better demonstrate its economy; At the same time, it has a wide adaptability and good comprehensive mechanical performance. However, there are many materials and equipment required for casting production (such as metals, wood, fuel, molding materials, etc.) and equipment (such as metallurgical furnaces, sand mixers, molding machines, core making machines, sand shakers, shot blasting machines, cast iron flat plates, etc.), which can produce dust, harmful gases, and noise, polluting the environment
There are many types of casting, which can be customarily divided into:
① Ordinary sand mold casting includes three types: wet sand mold, dry sand mold, and chemically hardened sand mold
② Special casting can be divided into two types based on the molding materials: special casting with natural mineral sand and gravel as the main molding material (such as investment casting, mud casting, shell casting in casting workshops, negative pressure casting, full mold casting, ceramic mold casting, etc.) and special casting with metal as the main molding material (such as metal mold casting, pressure casting, continuous casting, low-pressure casting, centrifugal casting, etc.)
2. The casting process usually includes:
① Preparation of casting molds (containers that turn liquid metals into solid castings), which can be divided into sand molds, metal molds, ceramic molds, mud molds, graphite molds, etc. according to the materials used; According to the number of uses, it can be divided into disposable, semi permanent, and permanent types. The quality of mold preparation is the main factor affecting the quality of castings
② The melting and pouring of cast metals, including cast iron, cast steel, and cast non-ferrous alloys
③ Casting treatment and inspection, including the removal of foreign objects on the core and surface of the casting, removal of the casting riser, scraping of burrs and burrs, as well as heat treatment, shaping, rust prevention treatment, and rough machining
2、 Forging
Forging is a processing method that uses forging machinery to apply pressure on metal billets, causing them to undergo plastic deformation in order to obtain forgings with certain mechanical properties, shape, and size. It is one of the two major components of forging
By forging, it is possible to eliminate as cast porosity and welding holes in the metal, and the mechanical properties of forgings are generally better than those of castings of the same material. In machinery, important parts with high loads and severe working conditions are mostly made of forgings, except for simple shapes that can be rolled into plates, profiles, or welded parts
1. Forging is divided by forming method
① Open forging (free forging)
There are mainly two types of forging, manual forging and mechanical forging, which use impact force or pressure to deform the metal between the upper and lower grinding blocks (anvils) to obtain the required forgings
② Closed mode forging
The metal billet undergoes compression deformation in a forging die chamber with a certain shape to obtain forgings, which can be divided into die forging, cold heading, rotary forging, extrusion, etc
2. Classified by deformation temperature
Forging can also be divided into hot forging (processing temperature higher than the recrystallization temperature of the billet metal), warm forging (lower than the recrystallization temperature), and cold forging (at room temperature)
The main materials used for forging are various components of carbon steel and alloy steel, followed by aluminum, magnesium, titanium, copper, and their alloys. The original state of materials includes bars, ingots, metal powders, and liquid metals. The ratio of the cross-sectional area of a metal before deformation to the cross-sectional area of the mold after deformation is called the forging ratio. The correct selection of forging ratio is closely related to improving product quality and reducing costs